Loam refers to soil that contains almost equal amounts of sand, clay and silt. Many gardeners consider it the ideal planting medium for growing most plants.
Soil is a mixture of small pieces of weathered rock. Sand is made up of the largest pieces, while clay is composed of the smallest pieces. The middle-size pieces form silt.
Sandy soil drains quickly, but soil with a large amount of clay drains slowly. Silt helps sandy soils to hold water, and it also helps clay soil to drain better.
Loam soil drains slowly enough that plants can absorb the water, but does not hold so much water that the plant roots rot.
Types of Loam Soil
Loam soil that has a higher percentage of one of the soil types is referred to as sandy loam, silty loam or clay loam, depending on which component is the largest.
Ball and Ribbon Tests
To determine which type of soil you have, moisten a handful of sand. If you can form a ball with the sand, you may have sandy or silty loam. If you can roll a ribbon of sand, you may have clay or silty clay loam. If you can form a ball and roll a ribbon with the sand, you may have loam or sandy clay loam.
- Texas A&M University Extension
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About this Author
Melody Lee worked as a newspaper reporter, copywriter and editor for 5 years. In addition, she has edited magazine articles and books. Lee holds a degree in landscape design and is a Florida master gardener. She has more than 25 years of gardening experience, which includes working at nurseries and greenhouses.